1. Field of the Invention
The present invention relates to an automatic barcode reader for documents.
2. Description of Related Art
Automated barcode reader devices are well known in the industry. These devices take the documents generally vertically stacked in a stacker and process them through a reading area one at a time. This reading area has at least one laser beam. The laser beam passes over and reads a series of printed bars forming a readable code or scan code. Based on a specific computer program, the readers can sort the data read from said bars according to one or more parameters determined by the program. They can also store the data or determine the route the item thus scanned has to follow to continue with its working proceedings. A number of these devices have document transport systems for processing documents through the reading area.
However, in most of these prior art devices, the documents scanned have a standard format of limited dimensions. Hence, the types of transport devices used with barcode readers are usually designed to process documents of similar characteristics, that is, dimensionally similar documents, such as a batch of invoices carrying a similar format or a batch of similar stubs. This limitation is due to the fact that the transport and sliding of documents are performed inside the transport machine through calibrated paths. The kinetic energy received by each individual document when being transported and the elements that make them go slower (friction, weight, etc.) need to be reasonably similar in these devices, since it is extremely important to ensure a steady speed of the document to be read in the reading area. Consequently, in the devices of the prior art the amount of movement given to each individual document generally should be similar for every document, since the mass is substantially similar in each document. With the processed documents being similar, the transport device manufacturer can thus ensure a predictable behavior for each document sliding or traveling inside their machines.
In the case of processing envelopes containing mail, this sliding and transporting task for the envelopes becomes difficult due to a number of reasons. First, the envelopes which have already been closed, with documents inside, are not usually evenly thick since there may be some differences within a certain range or format. Even when the envelopes are essentially equal in size and the location of the barcode to be read is in the same predetermined area, they may have one or more sheets of paper inside, thus resulting in the thicknesses of the envelopes varying. That is, some envelopes may contain only one sheet and others may contain two, three or more folded sheets. Consequently, their volume and mass vary. When this happens, both their thicknesses and their amount of movement will differ.
When the contents of the envelopes are similar, thickness variations are also essentially similar. This is crucial in the transport machines known in the prior art, since it is necessary to have an entrance opening to the reading area with a transversal section perpendicular to the document to be read, ensuring in this way the selection and transport of one document at a time. If two documents run together, one on top of the other, the document on the lower position is not read. However, it is usually the case that when there are uneven folds of paper or documents of different formats or clips in the envelope, there are also differences in thickness that obstruct the transport in the prior art transport machines. This is because all the existing transport machines have an entrance passage that restricts the thickness of the document, thus ensuring that only one document comes into the reading area at a time.
In summary, there are no transport devices or barcode readers for envelopes in the prior art that can read envelopes of different thicknesses, sizes or volumes within the same batch, at great speeds. Such prior art devices cannot ensure the transport of one envelope at a time through the reading beam when the envelopes differ in height or thickness depending on their contents.
If envelopes coming from different proceedings are sorted into batches of similar sizes, the different thicknesses of the envelopes may obstruct the normal functioning of traditional transport machines. Hence, it is desirable to have a new transport device to ensure that the envelopes come into the reading area of the laser beam one by one. These include envelopes of different acceptable sizes and thicknesses. Additionally, it is desirable to ensure that the output speed is greater than the input speed so as to avoid jams outside the reading area. This ensures a correct classification or selection of paths for the documents. This implies that the amount of movement to be given when leaving the reading area should be independent of the amount of movement initially given to the envelope. The amount of movement should be sufficient enough so as not to depend on the volume or mass of the envelope.
Hence, it is desirable to introduce new transport device which can read printed barcodes on envelopes that differ in height, size and thickness in the same batch. This new transport device should allow the transport of the envelopes one at a time at an acceptable speed, even when they are different in height, size or thicknesses, within a determined range. This new transport device should also permit their transport even when the different thicknesses and heights for a given envelope, e.g., thicker on one side than the other side of the same envelope.